The 2024 aluminum alloy, a structural material commonly used in aviation aircraft bodies, is susceptible to serious corrosion in marine atmospheric environments. This paper comprehensively studies the corrosion behavior of the 2024 aluminum alloy in the South China Sea atmosphere. Weighing, morphology observation, phase analysis, electrochemical testing, and other methods were used to study the corrosion law and corrosion mechanism of the 2024 aluminum alloy. The main conclusions are as follows: At the initial stage of exposure, pitting corrosion occurred on the surface of the 2024 aluminum alloy. After 3 months of exposure, the self-corrosion current density increased from 0.456 μA·cm⁻² to 8.338 μA·cm⁻². After 6 months of exposure, the corrosion developed into general corrosion. The main component of the corrosion product was Al₂O₃·3H₂O. The product covered the surface to form a loose corrosion product layer, which had an inhibitory effect on corrosion. The self-corrosion current density was reduced to 2.359 μA·cm⁻². After 12 months of exposure, the corrosion product layer fell off and became thinner, and the self-corrosion current density increased to 2.849 μA·cm⁻². The corrosion kinetics conformed to the functional equation W = 0.00346t^0.73891, indicating that the corrosion products have a certain protective effect on the matrix.

The hot corrosion experiments of René N5 alloy coated with three different NiCrAlY metal bonding layers are carried out, that the layers are prepared by different methods (APS, HVAF and MIP). Compared with bare René N5 alloy samples, the hot corrosion resistance of coated samples is improved. It can be attributed to the small internal stress of the surface oxide layer on the coating sample, which is difficult to spall, reducing the degree of hot corrosion reaction. The hot corrosion resistance of NiCrAlY layers is MIP > HVAF > APS, which is positively positively related to the density of layers, because the influence of element diffusion in the process of hot corrosion is effectively slowed down.

Municipal solid waste-to-energy (MSW-WTE) boilers are increasingly operated at higher steam temperatures and pressures to improve efficiency. Under these conditions, heat-transfer surfaces are exposed to high-temperature oxidation, chlorine-induced corrosion, molten-salt corrosion and thermomechanically coupled damage, which compromise long-term operational safety. Thermal spraying offers flexibility in tailoring coating composition and microstructure and is therefore widely used to improve the service reliability of these surfaces. This review examines the corrosive environments, principal damage mechanisms and development of thermal spray protection systems for MSW-WTE boiler heat-transfer surfaces. It first considers how variations in temperature, flue-gas composition and deposit evolution among boiler regions influence corrosion behavior, with particular emphasis on chlorine-induced active oxidation, sulfate/chloride-assisted hot corrosion and molten-salt corrosion. It then relates spraying processes and coating microstructures to the corrosion-protection mechanisms, advantages and limitations of MCrAlY, NiCr/NiCrMo and carbide-reinforced coatings under different service conditions. Finally, future developments in multifunctional coatings, structural optimization and condition-based maintenance are discussed. By linking corrosive environments, damage mechanisms, coating structures and service reliability, this review provides a framework for the design and engineering application of protective coatings for MSW-WTE boiler heat-transfer surfaces.